Support KXT image file export

[textures] Added SaveKTX()
[rlgl] Exposed rlGetGlTextureFormats()

src/rlgl.h

@@ -446,9 +446,11 @@ void rlLoadExtensions(void *loader);            // Load OpenGL extensions
 Vector3 rlUnproject(Vector3 source, Matrix proj, Matrix view);  // Get world coordinates from screen coordinates
 
 // Textures data management
-unsigned int rlLoadTexture(void *data, int width, int height, int format, int mipmapCount);    // Load texture in GPU
-void rlUpdateTexture(unsigned int id, int width, int height, int format, const void *data);    // Update GPU texture with new data
-void rlUnloadTexture(unsigned int id);
+unsigned int rlLoadTexture(void *data, int width, int height, int format, int mipmapCount); // Load texture in GPU
+void rlUpdateTexture(unsigned int id, int width, int height, int format, const void *data); // Update GPU texture with new data
+void rlGetGlTextureFormats(int format, unsigned int *glInternalFormat, unsigned int *glFormat, unsigned int *glType);  // Get OpenGL internal formats
+void rlUnloadTexture(unsigned int id);                              // Unload texture from GPU memory
+
 void rlGenerateMipmaps(Texture2D *texture);                         // Generate mipmap data for selected texture
 void *rlReadTexturePixels(Texture2D texture);                       // Read texture pixel data
 unsigned char *rlReadScreenPixels(int width, int height);           // Read screen pixel data (color buffer)
@@ -913,9 +915,6 @@ static void SetStereoView(int eye, Matrix matProjection, Matrix matModelView); /
 
 #endif  // defined(GRAPHICS_API_OPENGL_33) || defined(GRAPHICS_API_OPENGL_ES2)
 
-// Get OpenGL internal formats and data type from raylib PixelFormat
-static void GetGlFormats(int format, int *glInternalFormat, int *glFormat, int *glType);
-
 #if defined(GRAPHICS_API_OPENGL_11)
 static int GenerateMipmaps(unsigned char *data, int baseWidth, int baseHeight);
 static Color *GenNextMipmap(Color *srcData, int srcWidth, int srcHeight);
@@ -2015,8 +2014,8 @@ unsigned int rlLoadTexture(void *data, int width, int height, int format, int mi
     {
         unsigned int mipSize = GetPixelDataSize(mipWidth, mipHeight, format);
 
-        int glInternalFormat, glFormat, glType;
-        GetGlFormats(format, &glInternalFormat, &glFormat, &glType);
+        unsigned int glInternalFormat, glFormat, glType;
+        rlGetGlTextureFormats(format, &glInternalFormat, &glFormat, &glType);
 
         TraceLog(LOG_DEBUG, "Load mipmap level %i (%i x %i), size: %i, offset: %i", i, mipWidth, mipHeight, mipSize, mipOffset);
 
@@ -2105,8 +2104,8 @@ void rlUpdateTexture(unsigned int id, int width, int height, int format, const v
 {
     glBindTexture(GL_TEXTURE_2D, id);
 
-    int glInternalFormat, glFormat, glType;
-    GetGlFormats(format, &glInternalFormat, &glFormat, &glType);
+    unsigned int glInternalFormat, glFormat, glType;
+    rlGetGlTextureFormats(format, &glInternalFormat, &glFormat, &glType);
 
     if ((glInternalFormat != -1) && (format < COMPRESSED_DXT1_RGB))
     {
@@ -2115,13 +2114,64 @@ void rlUpdateTexture(unsigned int id, int width, int height, int format, const v
     else TraceLog(LOG_WARNING, "Texture format updating not supported");
 }
 
+// Get OpenGL internal formats and data type from raylib PixelFormat
+void rlGetGlTextureFormats(int format, unsigned int *glInternalFormat, unsigned int *glFormat, unsigned int *glType)
+{
+    *glInternalFormat = -1;
+    *glFormat = -1;
+    *glType = -1;
+
+    switch (format)
+    {
+    #if defined(GRAPHICS_API_OPENGL_11) || defined(GRAPHICS_API_OPENGL_21) || defined(GRAPHICS_API_OPENGL_ES2)
+        // NOTE: on OpenGL ES 2.0 (WebGL), internalFormat must match format and options allowed are: GL_LUMINANCE, GL_RGB, GL_RGBA
+        case UNCOMPRESSED_GRAYSCALE: *glInternalFormat = GL_LUMINANCE; *glFormat = GL_LUMINANCE; *glType = GL_UNSIGNED_BYTE; break;
+        case UNCOMPRESSED_GRAY_ALPHA: *glInternalFormat = GL_LUMINANCE_ALPHA; *glFormat = GL_LUMINANCE_ALPHA; *glType = GL_UNSIGNED_BYTE; break;
+        case UNCOMPRESSED_R5G6B5: *glInternalFormat = GL_RGB; *glFormat = GL_RGB; *glType = GL_UNSIGNED_SHORT_5_6_5; break;
+        case UNCOMPRESSED_R8G8B8: *glInternalFormat = GL_RGB; *glFormat = GL_RGB; *glType = GL_UNSIGNED_BYTE; break;
+        case UNCOMPRESSED_R5G5B5A1: *glInternalFormat = GL_RGBA; *glFormat = GL_RGBA; *glType = GL_UNSIGNED_SHORT_5_5_5_1; break;
+        case UNCOMPRESSED_R4G4B4A4: *glInternalFormat = GL_RGBA; *glFormat = GL_RGBA; *glType = GL_UNSIGNED_SHORT_4_4_4_4; break;
+        case UNCOMPRESSED_R8G8B8A8: *glInternalFormat = GL_RGBA; *glFormat = GL_RGBA; *glType = GL_UNSIGNED_BYTE; break;
+        #if !defined(GRAPHICS_API_OPENGL_11)
+        case UNCOMPRESSED_R32: if (texFloatSupported) *glInternalFormat = GL_LUMINANCE; *glFormat = GL_LUMINANCE; *glType = GL_FLOAT; break;   // NOTE: Requires extension OES_texture_float
+        case UNCOMPRESSED_R32G32B32: if (texFloatSupported) *glInternalFormat = GL_RGB; *glFormat = GL_RGB; *glType = GL_FLOAT; break;         // NOTE: Requires extension OES_texture_float
+        case UNCOMPRESSED_R32G32B32A32: if (texFloatSupported) *glInternalFormat = GL_RGBA; *glFormat = GL_RGBA; *glType = GL_FLOAT; break;    // NOTE: Requires extension OES_texture_float
+        #endif
+    #elif defined(GRAPHICS_API_OPENGL_33)
+        case UNCOMPRESSED_GRAYSCALE: *glInternalFormat = GL_R8; *glFormat = GL_RED; *glType = GL_UNSIGNED_BYTE; break;
+        case UNCOMPRESSED_GRAY_ALPHA: *glInternalFormat = GL_RG8; *glFormat = GL_RG; *glType = GL_UNSIGNED_BYTE; break;
+        case UNCOMPRESSED_R5G6B5: *glInternalFormat = GL_RGB565; *glFormat = GL_RGB; *glType = GL_UNSIGNED_SHORT_5_6_5; break;
+        case UNCOMPRESSED_R8G8B8: *glInternalFormat = GL_RGB8; *glFormat = GL_RGB; *glType = GL_UNSIGNED_BYTE; break;
+        case UNCOMPRESSED_R5G5B5A1: *glInternalFormat = GL_RGB5_A1; *glFormat = GL_RGBA; *glType = GL_UNSIGNED_SHORT_5_5_5_1; break;
+        case UNCOMPRESSED_R4G4B4A4: *glInternalFormat = GL_RGBA4; *glFormat = GL_RGBA; *glType = GL_UNSIGNED_SHORT_4_4_4_4; break;
+        case UNCOMPRESSED_R8G8B8A8: *glInternalFormat = GL_RGBA8; *glFormat = GL_RGBA; *glType = GL_UNSIGNED_BYTE; break;
+        case UNCOMPRESSED_R32: if (texFloatSupported) *glInternalFormat = GL_R32F; *glFormat = GL_RED; *glType = GL_FLOAT; break;
+        case UNCOMPRESSED_R32G32B32: if (texFloatSupported) *glInternalFormat = GL_RGB32F; *glFormat = GL_RGB; *glType = GL_FLOAT; break;
+        case UNCOMPRESSED_R32G32B32A32: if (texFloatSupported) *glInternalFormat = GL_RGBA32F; *glFormat = GL_RGBA; *glType = GL_FLOAT; break;
+    #endif
+        #if !defined(GRAPHICS_API_OPENGL_11)
+        case COMPRESSED_DXT1_RGB: if (texCompDXTSupported) *glInternalFormat = GL_COMPRESSED_RGB_S3TC_DXT1_EXT; break;
+        case COMPRESSED_DXT1_RGBA: if (texCompDXTSupported) *glInternalFormat = GL_COMPRESSED_RGBA_S3TC_DXT1_EXT; break;
+        case COMPRESSED_DXT3_RGBA: if (texCompDXTSupported) *glInternalFormat = GL_COMPRESSED_RGBA_S3TC_DXT3_EXT; break;
+        case COMPRESSED_DXT5_RGBA: if (texCompDXTSupported) *glInternalFormat = GL_COMPRESSED_RGBA_S3TC_DXT5_EXT; break;
+        case COMPRESSED_ETC1_RGB: if (texCompETC1Supported) *glInternalFormat = GL_ETC1_RGB8_OES; break;                      // NOTE: Requires OpenGL ES 2.0 or OpenGL 4.3
+        case COMPRESSED_ETC2_RGB: if (texCompETC2Supported) *glInternalFormat = GL_COMPRESSED_RGB8_ETC2; break;               // NOTE: Requires OpenGL ES 3.0 or OpenGL 4.3
+        case COMPRESSED_ETC2_EAC_RGBA: if (texCompETC2Supported) *glInternalFormat = GL_COMPRESSED_RGBA8_ETC2_EAC; break;     // NOTE: Requires OpenGL ES 3.0 or OpenGL 4.3
+        case COMPRESSED_PVRT_RGB: if (texCompPVRTSupported) *glInternalFormat = GL_COMPRESSED_RGB_PVRTC_4BPPV1_IMG; break;    // NOTE: Requires PowerVR GPU
+        case COMPRESSED_PVRT_RGBA: if (texCompPVRTSupported) *glInternalFormat = GL_COMPRESSED_RGBA_PVRTC_4BPPV1_IMG; break;  // NOTE: Requires PowerVR GPU
+        case COMPRESSED_ASTC_4x4_RGBA: if (texCompASTCSupported) *glInternalFormat = GL_COMPRESSED_RGBA_ASTC_4x4_KHR; break;  // NOTE: Requires OpenGL ES 3.1 or OpenGL 4.3
+        case COMPRESSED_ASTC_8x8_RGBA: if (texCompASTCSupported) *glInternalFormat = GL_COMPRESSED_RGBA_ASTC_8x8_KHR; break;  // NOTE: Requires OpenGL ES 3.1 or OpenGL 4.3
+        #endif
+        default: TraceLog(LOG_WARNING, "Texture format not supported"); break;
+    }
+}
+
 // Unload texture from GPU memory
 void rlUnloadTexture(unsigned int id)
 {
     if (id > 0) glDeleteTextures(1, &id);
 }
 
-
 // Load a texture to be used for rendering (fbo with color and depth attachments)
 RenderTexture2D rlLoadRenderTexture(int width, int height)
 {
@@ -2745,8 +2795,8 @@ void *rlReadTexturePixels(Texture2D texture)
     // GL_UNPACK_ALIGNMENT affects operations that write to OpenGL memory (glTexImage, etc.)
     glPixelStorei(GL_PACK_ALIGNMENT, 1);
 
-    int glInternalFormat, glFormat, glType;
-    GetGlFormats(texture.format, &glInternalFormat, &glFormat, &glType);
+    unsigned int glInternalFormat, glFormat, glType;
+    rlGetGlTextureFormats(texture.format, &glInternalFormat, &glFormat, &glType);
     unsigned int size = GetPixelDataSize(texture.width, texture.height, texture.format);
 
     if ((glInternalFormat != -1) && (texture.format < COMPRESSED_DXT1_RGB))
@@ -4591,58 +4641,6 @@ static void SetStereoView(int eye, Matrix matProjection, Matrix matModelView)
 
 #endif //defined(GRAPHICS_API_OPENGL_33) || defined(GRAPHICS_API_OPENGL_ES2)
 
-// Get OpenGL internal formats and data type from raylib PixelFormat
-static void GetGlFormats(int format, int *glInternalFormat, int *glFormat, int *glType)
-{
-    *glInternalFormat = -1;
-    *glFormat = -1;
-    *glType = -1;
-
-    switch (format)
-    {
-    #if defined(GRAPHICS_API_OPENGL_11) || defined(GRAPHICS_API_OPENGL_21) || defined(GRAPHICS_API_OPENGL_ES2)
-        // NOTE: on OpenGL ES 2.0 (WebGL), internalFormat must match format and options allowed are: GL_LUMINANCE, GL_RGB, GL_RGBA
-        case UNCOMPRESSED_GRAYSCALE: *glInternalFormat = GL_LUMINANCE; *glFormat = GL_LUMINANCE; *glType = GL_UNSIGNED_BYTE; break;
-        case UNCOMPRESSED_GRAY_ALPHA: *glInternalFormat = GL_LUMINANCE_ALPHA; *glFormat = GL_LUMINANCE_ALPHA; *glType = GL_UNSIGNED_BYTE; break;
-        case UNCOMPRESSED_R5G6B5: *glInternalFormat = GL_RGB; *glFormat = GL_RGB; *glType = GL_UNSIGNED_SHORT_5_6_5; break;
-        case UNCOMPRESSED_R8G8B8: *glInternalFormat = GL_RGB; *glFormat = GL_RGB; *glType = GL_UNSIGNED_BYTE; break;
-        case UNCOMPRESSED_R5G5B5A1: *glInternalFormat = GL_RGBA; *glFormat = GL_RGBA; *glType = GL_UNSIGNED_SHORT_5_5_5_1; break;
-        case UNCOMPRESSED_R4G4B4A4: *glInternalFormat = GL_RGBA; *glFormat = GL_RGBA; *glType = GL_UNSIGNED_SHORT_4_4_4_4; break;
-        case UNCOMPRESSED_R8G8B8A8: *glInternalFormat = GL_RGBA; *glFormat = GL_RGBA; *glType = GL_UNSIGNED_BYTE; break;
-        #if !defined(GRAPHICS_API_OPENGL_11)
-        case UNCOMPRESSED_R32: if (texFloatSupported) *glInternalFormat = GL_LUMINANCE; *glFormat = GL_LUMINANCE; *glType = GL_FLOAT; break;   // NOTE: Requires extension OES_texture_float
-        case UNCOMPRESSED_R32G32B32: if (texFloatSupported) *glInternalFormat = GL_RGB; *glFormat = GL_RGB; *glType = GL_FLOAT; break;         // NOTE: Requires extension OES_texture_float
-        case UNCOMPRESSED_R32G32B32A32: if (texFloatSupported) *glInternalFormat = GL_RGBA; *glFormat = GL_RGBA; *glType = GL_FLOAT; break;    // NOTE: Requires extension OES_texture_float
-        #endif
-    #elif defined(GRAPHICS_API_OPENGL_33)
-        case UNCOMPRESSED_GRAYSCALE: *glInternalFormat = GL_R8; *glFormat = GL_RED; *glType = GL_UNSIGNED_BYTE; break;
-        case UNCOMPRESSED_GRAY_ALPHA: *glInternalFormat = GL_RG8; *glFormat = GL_RG; *glType = GL_UNSIGNED_BYTE; break;
-        case UNCOMPRESSED_R5G6B5: *glInternalFormat = GL_RGB565; *glFormat = GL_RGB; *glType = GL_UNSIGNED_SHORT_5_6_5; break;
-        case UNCOMPRESSED_R8G8B8: *glInternalFormat = GL_RGB8; *glFormat = GL_RGB; *glType = GL_UNSIGNED_BYTE; break;
-        case UNCOMPRESSED_R5G5B5A1: *glInternalFormat = GL_RGB5_A1; *glFormat = GL_RGBA; *glType = GL_UNSIGNED_SHORT_5_5_5_1; break;
-        case UNCOMPRESSED_R4G4B4A4: *glInternalFormat = GL_RGBA4; *glFormat = GL_RGBA; *glType = GL_UNSIGNED_SHORT_4_4_4_4; break;
-        case UNCOMPRESSED_R8G8B8A8: *glInternalFormat = GL_RGBA8; *glFormat = GL_RGBA; *glType = GL_UNSIGNED_BYTE; break;
-        case UNCOMPRESSED_R32: if (texFloatSupported) *glInternalFormat = GL_R32F; *glFormat = GL_RED; *glType = GL_FLOAT; break;
-        case UNCOMPRESSED_R32G32B32: if (texFloatSupported) *glInternalFormat = GL_RGB32F; *glFormat = GL_RGB; *glType = GL_FLOAT; break;
-        case UNCOMPRESSED_R32G32B32A32: if (texFloatSupported) *glInternalFormat = GL_RGBA32F; *glFormat = GL_RGBA; *glType = GL_FLOAT; break;
-    #endif
-        #if !defined(GRAPHICS_API_OPENGL_11)
-        case COMPRESSED_DXT1_RGB: if (texCompDXTSupported) *glInternalFormat = GL_COMPRESSED_RGB_S3TC_DXT1_EXT; break;
-        case COMPRESSED_DXT1_RGBA: if (texCompDXTSupported) *glInternalFormat = GL_COMPRESSED_RGBA_S3TC_DXT1_EXT; break;
-        case COMPRESSED_DXT3_RGBA: if (texCompDXTSupported) *glInternalFormat = GL_COMPRESSED_RGBA_S3TC_DXT3_EXT; break;
-        case COMPRESSED_DXT5_RGBA: if (texCompDXTSupported) *glInternalFormat = GL_COMPRESSED_RGBA_S3TC_DXT5_EXT; break;
-        case COMPRESSED_ETC1_RGB: if (texCompETC1Supported) *glInternalFormat = GL_ETC1_RGB8_OES; break;                      // NOTE: Requires OpenGL ES 2.0 or OpenGL 4.3
-        case COMPRESSED_ETC2_RGB: if (texCompETC2Supported) *glInternalFormat = GL_COMPRESSED_RGB8_ETC2; break;               // NOTE: Requires OpenGL ES 3.0 or OpenGL 4.3
-        case COMPRESSED_ETC2_EAC_RGBA: if (texCompETC2Supported) *glInternalFormat = GL_COMPRESSED_RGBA8_ETC2_EAC; break;     // NOTE: Requires OpenGL ES 3.0 or OpenGL 4.3
-        case COMPRESSED_PVRT_RGB: if (texCompPVRTSupported) *glInternalFormat = GL_COMPRESSED_RGB_PVRTC_4BPPV1_IMG; break;    // NOTE: Requires PowerVR GPU
-        case COMPRESSED_PVRT_RGBA: if (texCompPVRTSupported) *glInternalFormat = GL_COMPRESSED_RGBA_PVRTC_4BPPV1_IMG; break;  // NOTE: Requires PowerVR GPU
-        case COMPRESSED_ASTC_4x4_RGBA: if (texCompASTCSupported) *glInternalFormat = GL_COMPRESSED_RGBA_ASTC_4x4_KHR; break;  // NOTE: Requires OpenGL ES 3.1 or OpenGL 4.3
-        case COMPRESSED_ASTC_8x8_RGBA: if (texCompASTCSupported) *glInternalFormat = GL_COMPRESSED_RGBA_ASTC_8x8_KHR; break;  // NOTE: Requires OpenGL ES 3.1 or OpenGL 4.3
-        #endif
-        default: TraceLog(LOG_WARNING, "Texture format not supported"); break;
-    }
-}
-
 #if defined(GRAPHICS_API_OPENGL_11)
 // Mipmaps data is generated after image data
 // NOTE: Only works with RGBA (4 bytes) data!

src/textures.c

@@ -148,6 +148,7 @@ static Image LoadPKM(const char *fileName);   // Load PKM file
 #endif
 #if defined(SUPPORT_FILEFORMAT_KTX)
 static Image LoadKTX(const char *fileName);   // Load KTX file
+static void SaveKTX(Image image, const char *fileName); // Save image data as KTX file
 #endif
 #if defined(SUPPORT_FILEFORMAT_PVR)
 static Image LoadPVR(const char *fileName);   // Load PVR file
@@ -726,10 +727,11 @@ void ExportImage(Image image, const char *fileName)
     if (IsFileExtension(fileName, ".png")) success = stbi_write_png(fileName, image.width, image.height, 4, imgData, image.width*4);
     else if (IsFileExtension(fileName, ".bmp")) success = stbi_write_bmp(fileName, image.width, image.height, 4, imgData);
     else if (IsFileExtension(fileName, ".tga")) success = stbi_write_tga(fileName, image.width, image.height, 4, imgData);
-    else if (IsFileExtension(fileName, ".jpg")) success = stbi_write_jpg(fileName, image.width, image.height, 4, imgData, 80);  // Between 1 and 100
+    else if (IsFileExtension(fileName, ".jpg")) success = stbi_write_jpg(fileName, image.width, image.height, 4, imgData, 80);  // JPG quality: between 1 and 100
+    else if (IsFileExtension(fileName, ".ktx")) SaveKTX(image, fileName);
     else if (IsFileExtension(fileName, ".raw")) 
     {
-        // Export raw pixel data
+        // Export raw pixel data (without header)
         // NOTE: It's up to the user to track image parameters
         FILE *rawFile = fopen(fileName, "wb");
         fwrite(image.data, GetPixelDataSize(image.width, image.height, image.format), 1, rawFile);
@@ -2932,6 +2934,93 @@ static Image LoadKTX(const char *fileName)
 
     return image;
 }
+
+// Save image data as KTX file
+// NOTE: By default KTX 1.1 spec is used, 2.0 is still on draft (01Oct2018)
+static void SaveKTX(Image image, const char *fileName)
+{
+    // KTX file Header (64 bytes)
+    // v1.1 - https://www.khronos.org/opengles/sdk/tools/KTX/file_format_spec/
+    // v2.0 - http://github.khronos.org/KTX-Specification/ - still on draft, not ready for implementation
+    
+    typedef struct {
+        char id[12];                        // Identifier: "«KTX 11»\r\n\x1A\n"             // KTX 2.0: "«KTX 22»\r\n\x1A\n"
+        unsigned int endianness;            // Little endian: 0x01 0x02 0x03 0x04
+        unsigned int glType;                // For compressed textures, glType must equal 0
+        unsigned int glTypeSize;            // For compressed texture data, usually 1
+        unsigned int glFormat;              // For compressed textures is 0
+        unsigned int glInternalFormat;      // Compressed internal format
+        unsigned int glBaseInternalFormat;  // Same as glFormat (RGB, RGBA, ALPHA...)       // KTX 2.0: UInt32 vkFormat
+        unsigned int width;                 // Texture image width in pixels
+        unsigned int height;                // Texture image height in pixels
+        unsigned int depth;                 // For 2D textures is 0
+        unsigned int elements;              // Number of array elements, usually 0
+        unsigned int faces;                 // Cubemap faces, for no-cubemap = 1
+        unsigned int mipmapLevels;          // Non-mipmapped textures = 1
+        unsigned int keyValueDataSize;      // Used to encode any arbitrary data...         // KTX 2.0: UInt32 levelOrder - ordering of the mipmap levels, usually 0
+                                                                                            // KTX 2.0: UInt32 supercompressionScheme - 0 (None), 1 (Crunch CRN), 2 (Zlib DEFLATE)...
+        // KTX 2.0 defines additional header elements...
+    } KTXHeader;
+
+    // NOTE: Before start of every mipmap data block, we have: unsigned int dataSize
+
+    FILE *ktxFile = fopen(fileName, "wb");
+
+    if (ktxFile == NULL) TraceLog(LOG_WARNING, "[%s] KTX image file could not be created", fileName);
+    else
+    {
+        KTXHeader ktxHeader;
+        
+        // KTX identifier (v2.2)
+        //unsigned char id[12] = { '«', 'K', 'T', 'X', ' ', '1', '1', '»', '\r', '\n', '\x1A', '\n' };
+        //unsigned char id[12] = { 0xAB, 0x4B, 0x54, 0x58, 0x20, 0x31, 0x31, 0xBB, 0x0D, 0x0A, 0x1A, 0x0A };
+        
+        // Get the image header
+        strcpy(ktxHeader.id, "«KTX 11»\r\n\x1A\n");     // KTX 1.1 signature
+        ktxHeader.endianness = 0;
+        ktxHeader.glType = 0;                   // Obtained from image.format
+        ktxHeader.glTypeSize = 1;
+        ktxHeader.glFormat = 0;                 // Obtained from image.format
+        ktxHeader.glInternalFormat = 0;         // Obtained from image.format
+        ktxHeader.glBaseInternalFormat = 0;
+        ktxHeader.width = image.width;
+        ktxHeader.height = image.height;
+        ktxHeader.depth = 0;
+        ktxHeader.elements = 0;
+        ktxHeader.faces = 1;
+        ktxHeader.mipmapLevels = image.mipmaps; // If it was 0, it means mipmaps should be generated on loading (not for compressed formats)
+        ktxHeader.keyValueDataSize = 0;         // No extra data after the header
+        
+        rlGetGlTextureFormats(image.format, &ktxHeader.glInternalFormat, &ktxHeader.glFormat, &ktxHeader.glType);   // rlgl module function
+        ktxHeader.glBaseInternalFormat = ktxHeader.glFormat;    // KTX 1.1 only
+        
+        // NOTE: We can save into a .ktx all PixelFormats supported by raylib, including compressed formats like DXT, ETC or ASTC
+        
+        if (ktxHeader.glFormat == -1) TraceLog(LOG_WARNING, "Image format not supported for KTX export.");
+        else
+        {
+            fwrite(&ktxHeader, 1, sizeof(KTXHeader), ktxFile);
+            
+            int width = image.width;
+            int height = image.height;
+            int dataOffset = 0;
+            
+            // Save all mipmaps data
+            for (int i = 0; i < image.mipmaps; i++)
+            {
+                unsigned int dataSize = GetPixelDataSize(width, height, image.format);
+                fwrite(&dataSize, 1, sizeof(unsigned int), ktxFile);
+                fwrite(image.data + dataOffset, 1, dataSize, ktxFile);
+                
+                width /= 2;
+                height /= 2;
+                dataOffset += dataSize;
+            }
+        }
+
+        fclose(ktxFile);    // Close file pointer
+    }
+}
 #endif
 
 #if defined(SUPPORT_FILEFORMAT_PVR)